Cooled enclosure

ABSTRACT

A cooled enclosure for housing heat generating devices, particularly solid state elements such as SCRs, diodes and other components, including a first chamber in which the heat generating devices are immersed in a refrigerant which will vaporize and abstract heat from the devices. The refrigerant vapor is condensed in a second chamber in which a heat exchanger is disposed, said heat exchanger being supplied with a liquid coolant. The condensed refrigerant then returns to the first chamber and is added to the body of liquid refrigerant in said chamber. An important feature of the invention is an alternate, secondary flow path for the refrigerant vapor through a secondary heat exchanger which is preferably air cooled. Under conditions when the ambient air is effective to condense refrigerant without operation of the primary liquid cooled heat exchanger, the vapor is condensed in such secondary heat exchanger and returned to the refrigerant bath in the first chamber.

Grandia 1 June 25, 1974 COOLED ENCLOSURE William M. Grandia, York, Pa.

[73] Assignee: Borg-Warner Corporation, Chicago,

. Ill.

[22] Filed: Sept. 18, 1972 [2]] Appl. No.1 290,028

[75] Inventor:

[52] US. Cl. 165/105, 317/100, 317/234 B [51] Int. Cl F28d 15/00, l-lOll1/12 [58] Field of Search...-.... l65/l05, 47 T; 317/234 A,

Primary ExaminerAlbcrt W. Davis, Jr. Assistant ExaminerS. J. RichterAttorney, Agent, or FirmD0nald W. Banner [57] ABSTRACT A cooledenclosure for housing heat generating devices, particularly solid stateelements such as SCRs. diodes and other components, including a firstchamber in which the heat generating devices are immersed in arefrigerant which will vaporize and abstract heat from the devices. Therefrigerant vapor is condensed in a second chamber in which a heatexchanger is disposed, said heat exchanger being supplied with a liquidcoolant. The condensed refrigerant then returns to the first chamber andis added to the body of liquid refrigerant in said chamber. An importantfeature of the invention is an alternate, secondary flow path for therefrigerant vapor through a secondary heat exchanger which is preferablyair cooled. Under conditions when the ambient air is effective tocondense refrigerant without operation of the primary liquid cooled heatexchanger, the vapor is condensed in such secondary heat exchanger andreturned to the refrigerant bath in the first chamber.

1 Claim, 3 Drawing Figures PATENlEnJuuzsmu sum 2 ar 2 FIGS 1 COOLEDENCLOSURE BACKGROUND AND SUMMARY OF THE INVENTION The use of solid statedevices such as silicon controlled rectifiers and diodes has beenincreasing in large power applications. Such applications would include,for example, power inverters for converting DC electrical energy to ACenergy and related motor controls which vary the frequency of the ACsupplied to the motors and accordingly vary the speed thereof. Suchapplications are increasingly important in transportation equipment,particularly for driving air conditioning compressor motors for suchequipment.

One particular troublesome problem is the dissipation of the heatgenerated by the aforementioned solid state components. The maintenanceof these devices at constant, relatively low temperature is essentialfor the proper operation of the same. Not only do high temper- Y aturesadversely affect their performance, but even variations in temperaturein the moderate range affect control and often result in erraticperformance.

It is an important object of this invention to provide a cooledenclosure for housing semi-conductor devices and similar solid statecomponents in a refrigerant cooled chamber. The devices are preferablycompletely immersed in a refrigerant which boils at a relatively lowtemperature and suitable means are provided for condensing the vaporizedrefrigerant and returning it to the main supply enveloping the heatgenerating devices. The industry has previously been reluctant to useany direct liquid cooled system because of the fear that contactwithliquid would ruin the SCRs. However, I have discovered that the use ofconventional halogenated hydrocarbon refrigerants such as R-l2, R-22,R-l 14 etc. have no deleterious effect. These refrigerants arestable,-non-corrosive and have a high dielectric coefficient, all suchfactors being required in the particular environment.

An important feature of the invention is the use of an alternate flowpath for refrigerant vapor through a secondary, air cooled heat exchangesystem so that the primary heat exchanger can be discontinued when theambicnt air is effective to condense the refrigerant.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view, withcertain portions being broken away, of the improved enclosure formingthe subject of the present invention;

FIG. 2 is a cross-sectional view taken generally along the plane of line2--2 of FIG. 1; and

FIG. 3 is a cross-sectional view taken generally along the plane of line33 of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION Referring first to FIG. 1 there isshown a cooled enclosure comprising a plurality of generally cylindricalshells l2 defining primary chambers 14 in which the solid statecomponents 16 are disposed. Each shell is closed by cap members 18 and20 at opposite ends thereof, the front cap member 18 being secured tothe shell by means of fasteners 22. The electrical bus bar connections24 also extend through the front cap to a source of electrical power andlogic circuits (not shown) housed in casing 26.

Extending transversely across each of the shells l2 and in fluidcommunication therewith is a primary heat exchanger 30 including a shell32 and a tube 34 arranged therein through which a cooled medium such aswater-or refrigerant is circulated. The openings between the primaryheat exchanger 30 and the individual shells 12 are designated at 36(FIG. 2). Connected by conduit 37 to the primary heat exchanger is avapor collecting header 38. A plurality of secondary heat exchangers 40interconnect header 38 with a second header 42 through the length of theassembly. Each of the heat exchangers 40 is preferably provided with afinned surface 44 or other means for promoting heat transfer betweenambient air and vapor flowing through the tube. Condensate collectingheader 42 is connected to the lower portion of the shells 12 by means ofconduit 46 and condensate return pipe 48 which connects with each of theshells.

The solid state components 16 are submerged within a liquid refrigerantbath 50 maintained at any desired level. It has been found that suchdevices will operate very efficiently if they are completely submergedwithin the bath.

OPERATION During normal operation, the primary heat exchanger 30 issupplied with a cooling medium which flows continuously through coil 34.As the solid state devices 16 are energized they liberate greatquantities of heat which is passed through heat sinks into the body ofliquid refrigerant 50. The refrigerant boils and flows into primary heatexchanger 30 where it condenses on the coil 34 and drops back as aliquid through communicating openings 36. Under some conditions, whenatmospheric air is cool enough, the primary heat exchanger 30 may bediscontinued. The air flowing over the surface of the secondary heatexchanger tubes 40 is effective to condense fluid which passes intoheader 38 and down through the tubes into the condensate receivingheader 42. The liquid refrigerant then is collected in the header andtransferred to the shells through conduits 46 and 48.

While the invention has been described in connection with a certainspecific embodiment thereof, it is to be understood that this is by wayof illustration and not by way of limitation; and the scope of theappended claims should be construed as broadly as the prior art willpermit.

What is claimed is:

l. A cooled enclosure for housing heat generating devices comprising: aplurality of spaced, generally cylindrical shells defining primarychambers in which said heat generating devices are located; a primaryheat exchanger extending traversely of said shells and communicatingtherewith through openings adjacent the top of each said shell, saidheat exchanger including a coil through which a liquid coolant isadapted to be circulated; a vapor collecting header connected to saidprimary heat exchanger; a condensate collecting header; a plurality ofair-cooled heat exchangers interconnecting said vapor collecting header'and said condensate collecting header, said heat exchangers beingprovided with a heat transfer surface for promoting heat transferbetween ambient air and vapor flowing through said heat exchangers;means for returning condensate from said collecting header to saidshells; and a body of halogenated hydrocarbon refrigerant in saidprimary cham- 3 ,8 I 8,98 3 3 4 bers in contact with said heatgenerating devices changers when said ambient air is effective tocondense whereby refrigerant vapor generated in said primary saidrefrigerant without operation of said primary heat chambers may becondensed in said primary heat exexchanger.

changer or alternatively by said air-cooled heat ex-

1. A cooled enclosure for housing heat generating devices comprising: aplurality of spaced, generally cylindrical shells defining primarychambers in which said heat generating devices are located; a primaryheat exchanger extending traversely of said shells and communicatingtherewith through openings adjacent the top of each said shell, saidheat exchanger including a coil through which a liquid coolant isadapted to be circulated; a vapor collecting header connected to saidprimary heat exchanger; a condensate collecting header; a plurality ofair-cooled heat exchangers interconnecting said vapor collecting headerand said condensate collecting header, said heat exchangers beingprovided with a heat transfer surface for promoting heat transferbetween ambient air and vapor flowing through said heat exchangers;means for returning condensate from said collecting header to saidshells; and a body of halogenated hydrocarbon refrigerant in saidprimary chambers in contact with said heat Generating devices wherebyrefrigerant vapor generated in said primary chambers may be condensed insaid primary heat exchanger or alternatively by said air-cooled heatexchangers when said ambient air is effective to condense saidrefrigerant without operation of said primary heat exchanger.